Dear friend, welcome to HCM,
if repeat blood sugar is also high, you should see your doc and probably get admitted if urine/ blood test
shows acidosis/ ketonuria
your doc would look for serious complications like DKA/ Hyperosmolar state.
good that you already advised avoiding sugars. she will need insulin
and work up to look for causes for this shoot-up.
I hope to have guided you in right direction.
take care and keep me posted on your progress.
good luck !